Wagering system with volatility adjustment

ABSTRACT

Gaming systems, methods, and software are provided which adjust the volatility of a gaming machine based on the player&#39;s current bankroll. A preferred embodiment includes a method that determines a game player&#39;s bankroll amount including cash or credits available for wagering. It then determines the desired payout volatility based on the game player&#39;s bankroll amount. From the desired volatility, the method selects a payout table based on the desired volatility. The method then includes receiving a wager input from the player effective to place a wager and conduct a game at a player station with the selected payout table. In some versions, a paytable may be selected directly using bankroll information, without the intermediate step of identifying a desired volatility level. Further, other factors may be considered in choosing the desired volatility or paytable.

TECHNICAL FIELD OF THE INVENTION

This invention relates to wagering systems such as slot machine systems that vary payout volatility based on certain player characteristics.

BACKGROUND OF THE INVENTION

Different types of gaming machines have been developed that may change the payout distribution, or paytable, used to award results for player's wagers. One such system is described in U.S. patent application Ser. No. 11/531,222, by Brian Watkins, filed Sep. 12, 2006, and entitled “METHOD AND APPARATUS FOR PRESENTING BINGO GAMING RESULTS USING MULTIPLE PRIZE DISTRIBUTIONS.” This application describes a bingo player terminal that operates operations in two different game states with different pattern tables. The system changes states based on game results, thereby changing the bingo pattern table that is used to award results in the game. Other games have also been developed that change the operating paytable based on game outcomes.

Changing the active paytable in a game will often change the payout volatility of the game, thereby varying the frequency and size of payouts. One common way to measure such a change is to calculate a “volatility index,” which is a mathematical value used to measure the distribution of sizes and probabilities of slot machine payouts. (This value may also be referred to simply as “volatility.”) For example, many slot machines have a relatively steady payout progression and therefore have low volatility indices. This means there is a relatively steady progression of many payoff values from the lowest to the highest, with each payoff corresponding probability decreasing as the value of the payoff increases. “Expected value” (“EV”) is another mathematical value used in the industry to describe the probability-weighted average of all possible outcomes of a chance event. That is, the EV is often defined as the percentage of the total wager that the machine will pay out over the cycle of the game, where the cycle is defined to be the set of all outcomes possible in the game. In one respect, the volatility is used to refer to the standard deviation of the distribution of possible values about the expected value. Methods of calculating the volatility index and EV are known in the art, and are described, for example, in the book Casino Operations Management, Second Edition, by Jim Kilby, Jim Fox, and Anthony Lucas (2004, Wiley Publishers). This book describes ways of calculating volatility at pages 125-126. This description and the entire book Casino Operations Management are hereby incorporated by reference in this application for all purposes.

Game manufacturers are continuously pressed to develop new game presentations, formats, and game graphics in an attempt to provide high entertainment value for players and thereby attract and keep players. Typically different game titles in different formats will provide a volatility level that players can become familiar with. For example, a player may know that a certain game provides small prizes but awards prizes often, while another game may be known to provide a greater number of large prizes, but award them less frequently. What is needed is various ways to increase the excitement of gaming by providing wagering games with varying volatility.

SUMMARY OF THE INVENTION

Gaming systems, methods, and software are provided that adjust the volatility of a gaming machine based on the player's current bankroll. A preferred embodiment includes a method that determines a game player's bankroll amount including cash or credits available for wagering. It then determines the desired payout volatility based on the game player's bankroll amount. From the desired volatility, the method selects a payout table based on the desired volatility. The method then includes receiving a wager input from the player effective to place a wager and conduct a game at the player station with the selected payout table. The desired volatility is typically determined after detecting a change in the game player's bankroll level, but may be conducted at any suitable step in the game play cycle that includes a wager, conducting a game, and awarding a result.

In some versions, a paytable may be selected directly using bankroll information, without the intermediate step of identifying a desired volatility level. Even in such a situation, a desired volatility is implied on the conditions that the paytables have different volatilities and the paytables are being chosen because of their volatility. Further, other factors may be considered in choosing the desired volatility or paytable. The process may employ changes in the player's bet size as an indication that the player is more or less risk averse, and change the volatility accordingly. Other factors may also be considered or combined in some metric to indicate how risk averse a player may be, and such measurement may be used together with the bankroll size to determine a desired volatility or choose a paytable. Another factor that may be used in determining any volatility adjustment is the length of the player's gaming session. The time of day may also be used, with different volatilities given at closing time or near meals. The direction of changes in player's bankroll, and the rate of change in a player's bankroll, may also be considered. Other aspects of the player's history may also be taken into account, such as their typical betting amount or the type of gaming machines at which they typically play (especially whether they prefer high or low volatility machines). The decision may also take into account the number of possible wagers remaining in a player's bankroll. Yet another factor that may be added into the determination of what desired volatility to use is the player's movement between gaming machines. That is, moving to a different gaming machine may sometimes be interpreted as the player's desire to play a different game with a different volatility. Any of the above-listed factors may be used separately or together in any subcombination with the player's bankroll in the process of determining the desired volatility.

A method embodying principles of the invention may be implemented in a gaming machine using one or more display devices such as CRTs, LCDs, plasma displays, or other types of video display devices. The display device or devices are used to present the game results, but in some cases will present some visual indicator that the volatility has changed. Other embodiments may not provide an indicator. As used in this disclosure and the accompanying claims, a gaming machine through which the present invention may be implemented will be referred to generally as a gaming machine regardless of the nature of the display device arrangement used to display graphical elements of the game to the player, and regardless of the manner in which the display device arrangement operates.

A gaming system according to one embodiment includes (i) a display arrangement having one or more display devices, (ii) a player input device arrangement having one or more player input devices, and (iii) a game controller arrangement. The gaming controller arrangement may cooperate with a server to accomplish one or more if its functions. The controller conducts the game by causing the display device to display the game and subsequent results. The controller also implements the decision of whether to adjust payout volatility based on the methods disclosed herein. Different implementations may implement different parts of the gaming controller arrangement on the gaming machine or the gaming server.

The present invention may also be embodied in a program product stored in one or more computer readable media. That is, the invention may take the form of a computer program that can be installed and run on one or more machines. A preferred computer program version of the invention includes several software modules or sections referred to as “program code.” This version of the program product includes gaming activation program code executable for receiving a wager input from the player on the gaming machine's special purpose input hardware. Also included is the game controller program code executable for conducting the wagering game. Award program code is included executable for, in response to determining a winning result, awarding a wager win result to the player. Volatility adjustment program code is included to adjust the volatility according to the methods disclosed herein. Also included is display control program code executable for causing a display arrangement to (i) display the conduct of the wagering game and (ii) display the results of the wagering game.

These and other advantages and features of the invention will be apparent from the following description of the preferred embodiments, considered along with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view in front perspective of a gaming machine which may be used in a gaming system embodying the principles of the present invention.

FIG. 2 is a block diagram showing various electronic components of the gaming machine shown in FIG. 1.

FIG. 3 is a block diagram showing a network arrangement connecting a number of gaming machines according to one embodiment of the present invention.

FIG. 4 is a flowchart of a volatility adjustment process that may be performed according to one embodiment of the present invention.

FIG. 5 shows two data tables that may be used in different embodiments of the variable volatility process of the present invention.

FIG. 6 is a flow chart of a volatility adjustment process according to another embodiment of the invention.

DESCRIPTION OF PREFERRED EMBODIMENTS

FIG. 1 shows a gaming machine 100 that may be used to implement a volatility adjustment process according to the present invention. The block diagram of FIG. 2 shows further details of gaming machine 100. Referring to FIG. 1, gaming machine 100 includes a cabinet 101 having a front side generally shown at reference numeral 102. A primary video display device 104 is mounted in a central portion of the front surface 102, with a ledge 106 positioned below the primary video display device and projecting forwardly from the plane of the primary video display device. In addition to primary video display device 104, the illustrated gaming machine 100 includes a secondary video display device 107 positioned above the primary video display device. Gaming machine 100 also includes two additional smaller auxiliary display devices, an upper auxiliary display device 108 and a lower auxiliary display device 109. It should also be noted that each display device referenced herein may include any suitable display device including a cathode ray tube, liquid crystal display, plasma display, LED display, or any other type of display device currently known or that may be developed in the future.

Gaming machine 100, illustrated in FIG. 1, also includes a number of mechanical control buttons 110 mounted on ledge 106. These control buttons 110 may allow a player to select a bet level, select pay lines, select a type of game or game feature, and actually start a play in a primary game. Other forms of gaming machines according to the invention may include switches, joysticks, or other mechanical input devices, and/or virtual buttons and other controls implemented on a suitable touch screen video display. For example, primary video display device 104 in gaming machine 100 provides a convenient display device for implementing touch screen controls.

It will be appreciated that gaming machines may also include a number of other player interface devices in addition to devices that are considered player controls for use in playing a particular game. Gaming machine 100 also includes a currency/voucher acceptor having an input ramp 112, a player card reader having a player card input 114, and a voucher/receipt printer having a voucher/receipt output 115. Audio speakers 116 generate an audio output to enhance the user's playing experience. Numerous other types of devices may be included in gaming 2 machines that may be used according to the present invention.

FIG. 2 shows that gaming machine 100 includes a central processing unit (CPU) 205 along with random access memory (RAM) 206 and nonvolatile memory or storage device 207. All of these devices are connected on a system bus 208 with an audio interface device 209, a network interface 210, and a serial interface 211. A graphics processor 215 is also connected on bus 208 and is connected to drive primary video display device 104 and secondary video display device 107 (both mounted on cabinet 101 as shown in FIG. 1). A second graphics processor 216 is also connected on bus 208 in this example to drive the auxiliary display devices 108 and 109 also shown in FIG. 1. As shown in FIG. 2, gaming machine 100 also includes a touch screen controller 217 connected to system bus 208. Touch screen controller 217 is also connected via signal path 218 to receive signals from a touch screen element associated with primary video display device 104. It will be appreciated that the touch screen element itself typically comprises a thin film that is secured over the display surface of primary video display device 104. The touch screen element itself is not illustrated or referenced separately in the figures.

Those familiar with data processing devices and systems will appreciate that other basic electronic components will be included in gaming machine 100 such as a power supply, cooling systems for the various system components, audio amplifiers, and other devices that are common in gaming machines. These additional devices are omitted from the drawings so as not to obscure the present invention in unnecessary detail.

All of the elements 205, 206, 207, 208, 209, 210, and 211 shown in FIG. 2 are elements commonly associated with a personal computer. These elements are preferably mounted on a standard personal computer chassis and housed in a standard personal computer housing which is itself mounted in cabinet 101 shown in FIG. 1. Alternatively, the various electronic components may be mounted on one or more circuit boards housed within cabinet 101 without a separate enclosure such as those found in personal computers. Those familiar with data processing systems and the various data processing elements shown in FIG. 2 will appreciate that many variations on this illustrated structure may be used within the scope of the present invention. For example, since serial communications are commonly employed to communicate with a touch screen controller such as touch screen controller 217, the touch screen controller may not be connected on system bus 208, but instead include a serial communications line to serial interface 211, which may be a USB controller or a IEEE 1394 controller for example. It will also be appreciated that some of the devices shown in FIG. 2 as being connected directly on system bus 208 may in fact communicate with the other system components through a suitable expansion bus. Audio interface 209, for example, may be connected to the system via a PCI bus. System bus 208 is shown in FIG. 2 merely to indicate that the various components are connected in some fashion for communication with CPU 205 and is not intended to limit the invention to any particular bus architecture. Numerous other variations in the gaming machine internal structure and system may be used without departing from the principles of the present invention.

It will also be appreciated that graphics processors are also commonly a part of modern computer systems. Although separate graphics processor 215 is shown for controlling primary video display device 104 and secondary video display device 107, and graphics processor 216 is shown for controlling both auxiliary display devices 108 and 109, it will be appreciated that CPU 205 may control all of the display devices directly without any intermediate graphics processor. The invention is not limited to any particular arrangement of processing devices for controlling the video display devices included with gaming machine 100. Also, a gaming machine implementing the present invention is not limited to any particular number of video display devices or other types of display devices, provided some display arrangement is included for displaying the symbol shifting graphic, the selectable objects, and the display modifications resulting from the selection of the various selectable objects.

In the illustrated gaming machine 100, CPU 205 executes software which ultimately controls the entire gaming machine including the receipt of player inputs and the presentation of the graphic symbols displayed according to the invention through display devices 104, 107, 108, and 109 associated with the gaming machine. As will be discussed further below, CPU 205 either alone or in combination with graphics processor 215 may implement a presentation controller for performing functions associated with a primary game that may be available through the gaming machine and may also implement a game client for directing one or more display devices at the gaming machine to display portions of a volatility adjustment process according to the present invention. CPU 205 also executes software related to communications handled through network interface 210, and software related to various peripheral devices such as those connected to the system through audio interface 209, serial interface 211, and touch screen controller 217. CPU 205 may also execute software to perform accounting functions associated with game play. Random access memory 206 provides memory for use by CPU 205 in executing its various software programs while nonvolatile memory or storage device 207 may comprise a hard drive or other mass storage device providing storage for programs not in use or for other data generated or used in the course of gaming machine operation. Network interface 210 provides an interface to other components of a gaming system in which gaming machine 100 is included. In particular, network interface 210 provides an interface to a game server which controls certain aspects of the multiplayer, variable volatility adjustment process as will be discussed below in connection with FIG. 3.

It should be noted that the invention is not limited to gaming machines employing the personal computer-type arrangement of processing devices and interfaces shown in example gaming machine 100. Other gaming machines through which a variable volatility adjustment process is implemented may include one or more special purpose processing devices to perform the various processing steps for implementing the present invention. Unlike general purpose processing devices such as CPU 205, these special purpose processing devices may not employ operational program code to direct the various processing steps.

Referring now to FIG. 3, a gaming system 300 according to the present invention includes a number of gaming machines 100 in this example implementation. For purposes of describing system 300, each gaming machine 100 in FIG. 3 is shown as including a video display device 107 and a player interface that may include buttons, switches, or other physical controls and/or touch screen controls as discussed above in connection with FIG. 1. This player interface is labeled 301 in FIG. 3. System 300 further includes a game server 302 and a respective game client 303 (abbreviated “GC” in FIG. 3) included with each respective gaming machine 100. In the form of the invention shown in FIG. 3, these two components, game 8 server 302 and game client components 303, combine to implement a game control arrangement which will be described in detail below. System 300 also includes an award controller 305, which is shown in FIG. 3 as being associated with game server 302 to indicate that the two components may be implemented through a common data processing device/computer system. Gaming machines 100, game server 302, and award controller 305 are connected in a network communication arrangement including first and second network switches 306 and 307, connected together through various wired or wireless signal paths, all shown as communications links 308 in FIG. 3.

Each gaming machine 100, and particularly player interface 301 associated with each gaming machine, allows a player to make any inputs that may be required to make the respective gaming machine eligible for a volatility adjustment process as described herein. Player interface 301 also allows a player at the gaming machine to initiate plays in a primary game available through the gaming machine. The respective video display device 107 associated with each respective gaming machine 100 is used according to the invention to generate the graphic displays to show the various elements of the games in progress, and gaming results, at the various gaming machines.

The game control arrangement made up of game server 302 and the respective game client 303 at a given gaming machine functions to control the respective video display device 107 for that gaming machine to display a symbol shifting symbol matrix according to the techniques described herein. In preferred embodiments, an award controller 305 is responsible for implementing a player's participation in a volatility adjustment process, and maintaining historical data employed in certain versions of the volatility adjustment process. In some embodiments, parts or all of the volatility adjustment process may be performed in the game controller 303 of each machine 100, as will be further described below.

Various implementations of the present invention employ various communications between game server 302 and the various gaming machines 100 included in system 300. The network arrangement made up of network switches 306 and 307, and the various communication links 308 shown in FIG. 3 is illustrated merely as an example of a suitable communications arrangement. The present invention is not limited to any particular communications arrangement for facilitating communications between game server 302 and various gaming machines 100. Any wired or wireless communication arrangement employing any suitable communications protocols (such as TCP/IP for example) may be used in an apparatus according to the invention.

The example system 300 shown in FIG. 3 shows two different groups of four gaming machines 100, but this is not limiting and typically a game server and award controller will service many more gaming machines. FIG. 3 shows other server(s) 310 included in the network. This illustrated “other server(s)” element 310 may include one or more data processing devices for performing various functions related to games conducted through system 300 and any other games that may be available to players through gaming machines 100. For example, apparatus 300 may provide support for cashless gaming or various forms of mixed cash/cashless gaming through the various gaming machines 100. In this example, one or more other servers 310 will be included in apparatus 300 for supporting these types of wagering and payout systems. As another example, the various gaming machines 100 included in system 300 may allow players to participate in a game (primary game) other than a volatility adjustment process, and this other game may rely on a result identified at or in cooperation with a device that is remote from the gaming machines. In this example, another server 310 may be included in the system for identifying results for the primary game and communicating those results to the various gaming machines 100 as necessary. Generally, the other server(s) 310 shown in FIG. 3 are shown only to indicate that numerous other components may be included along with the elements that participate in providing volatility adjustment process according to the present invention. Other server(s) 310 may provide record keeping, player tracking, accounting, or result identifying services, or any other services that may be useful or necessary in a gaming system.

FIG. 4 is a flowchart 400 of a volatility adjustment process that may be performed at the various gaming machines 100 included in gaming system 300 shown in FIG. 3. In particular, process 400 illustrates the interaction between a primary game that may be available at a respective gaming machine 100, and a volatility adjustment process implemented through the gaming machine. The player logs in at gaming machine 100 or otherwise activates the gaming machine as indicated at process block 402. Next at process block 404, the process determines the bankroll amount available to the player, either from the amount deposited at the gaming machine, or from a player account. This bankroll amount is used to determine a desired volatility to be used with the player's wagers, as indicated at block 405. This process will be described in further detail below. After a desired volatility is determined, a paytable is chosen to be used in the player's first wager at block 406. This choice is made based at least upon the desired volatility, as will be further discussed.

With the paytable chosen at block 406, the process receives the first wager from the player as shown at block 408. In response to the wager, the process determines a gameplay result (block 410), which may include base and bonus game results as is known in the art. This result is applied to the previously selected paytable to produce a payout amount due to the player in response to their wager, as shown at process block 412. At this point, the player's bankroll may have changed, because either their original wager was lost, or a prize was won which may increase the player's bankroll. At block 414, the process determines if the player's bankroll level has changed (for example, changed levels from a set of defined levels such as high, medium, and low). If so, the process determined a new desired volatility level based on the new bankroll level (block 416). Next, at block 418, the new desired volatility level is used to choose a new paytable. At this point, the game is ready to receive the next wager from the player and returns to block 408. In such a manner, the wagering or payout volatility of the gaming machine is adjusted based on the bankroll deposited by the player.

FIG. 5 shows two data tables that may be used in different embodiments of the variable volatility process. The depicted data tables, or other suitable data structure, are used to determine the desired volatility (i.e., block 416 in FIG. 4) and to determine a payout table, or paytable, based on the desired volatility (block 418 in FIG. 4).

Table 501 is a data table having, in this embodiment, three columns. The first column, the Game Player Bankroll, is used as the index to the table to look up the other values. That is, when the volatility adjustment process of this embodiment needs to determine what volatility and associated paytable are needed (blocks 416 and 418 in FIG. 4, for example), it uses the current player payroll level to look up access table 501 and look up the Desired Volatility and associated Payout Table to be used. The Game Player Bankroll field may be implemented in a variety of ways, such as using a range of the actual credit values in the bankroll, or using a metric indicating the same. As an example of a version using a range of credits, the Large Bankroll field identified in table 501 may contain simply a lookup range in credit denominations for the current game, such as, for example, the range of 1000 credits to the maximum bankroll. The Medium Bankroll value may contain the range of 500 credits to 999 credits, and the Small Bankroll value may contain the range of 1 credit to 499 credits. In such implementation, when the bankroll changes (for example, block 414 in FIG. 4), the new bankroll is used to access table 501 and used as an index. For example, if a prize were awarded and the bankroll changed from 450 credits to 550 credits, the volatility adjustment process would use the new bankroll value of 550 credits to index table 501, would index into the example ranges described above and determine that a medium bankroll is now in use, and would look up the desired volatility value and the payout table associated with the medium bankroll level.

The second column in the depicted table 501 is the Desired Volatility column. Some versions of the volatility adjustment process may not explicitly include a desired volatility value such as that held in the data fields of the Desired Volatility column, and instead may simply directly look up a payout table to use based on the player bankroll. In such case, the newly selected paytable has been provided in the table because it has a specific associated payout volatility that provides the desired volatility for each bankroll level. Other embodiments, such as that shown, may explicitly identify a desired volatility. Such a scheme may be useful, for example, in abstracting the paytables from the bankroll levels, providing ability to change the paytables for a particular volatility level, or provide multiple alternative paytables for a desired volatility level. The fields in this column each hold a value indicating (for different embodiments) either a volatility value, a volatility range, or a metric of a desired value or range such as the example metric values of High, Medium, and Low that are shown in table 501.

The third column in table 501 is the Payout Table Used column. This provides a link or identifier to a respective paytable stored locally or on the gaming network, to be used for each respective bankroll level in the table. The paytables identified here are constructed such that they provide the desired volatility. In this embodiment, when the player's bankroll is high, the volatility adjustment process provides a paytable with a high volatility, and when the bankroll is low the process provides a low volatility.

Table 502 has similar data to that of table 501, but includes another level for a minimal bankroll, that is, a bankroll that will only provide a few wagers. Table 502 provides that the volatility adjustment process changes the volatility back to high when the player bankroll is reduced to this level, for providing the player a chance for a bigger win that could possibly replenish their bankroll. Note that in preferred embodiments, while the various paytables used have different volatilities, they have the same payout percentage (or hold amount). That is, wagering games typically provide some form of notice regarding the payout percentage and this preferably should not be changed over the course of play, unless in some allowed circumstances such as a bonus game or a “hot” game mode with a different advertised payout percentage. In other embodiments, the different paytables may in fact have different payout percentages. This should be done only when properly advertised to the player and approved by regulatory authorities. While two different embodiments are depicted having a certain number of paytables, this is not limiting and various embodiments may have fewer or many more volatility levels associated with different paytables. Also, while the depicted embodiments generally show a higher volatility level with a higher bankroll, other embodiments may sometimes provide a lower volatility level with a higher bankroll, or have a distribution of volatility levels that is related inversely to the bankroll levels. The correlation between volatility level and bankroll level may also vary—that is, volatility may rise with bankroll to a certain level, and then fall as bankroll rises, and then rise again. That is, the desired volatility may vary proportionally to bankroll at some bankroll ranges, and vary inversely at other ranges. The depicted scheme in table 502 has one uneven point in the distribution because the lowest bankroll level is associated with the high volatility level as discussed above. Note that while a table is shown, this is not limiting and any suitable data structure or structures may be used, stored on computer readable medium, if it is suitable to express the relationships described may be used. For example, the table may be in the form of a database, or may be in the form of individual data structures to represent each row of the depicted tables.

FIG. 6 is a flow chart of a volatility adjustment process according to another embodiment of the invention. The depicted process 600 is similar to that of FIG. 4, but illustrates some variations that may be made to the process by considering additional factors in the volatility adjustment decision (at block 616, further described below). Process 600 begins when the player logs in at gaming machine 100 or otherwise activates the gaming machine as indicated at process block 602. Next at process block 604, the process determines the bankroll amount available to the player, either from the amount deposited at the gaming machine, or from a player account. This amount is used to determine a desired volatility to be used with the player's wagers, as indicated at block 605. After a desired volatility is determined, a paytable is chosen to be used in the player's first wager at block 606. This choice is made based at least upon the desired volatility, as will be further discussed.

With the paytable chosen at block 606, the process receives the first wager from the player as shown at block 608. In response to the wager, the process determines a game play result (block 610), which may include base and bonus game results as is known in the art. This result is applied to the previously selected paytable to produce a payout amount due to the player 8 in response to their wager, as shown at process block 612. At this point, the player's bankroll may have changed, because either their original wager was lost, or a prize was won which may increase the player's bankroll. At block 614, the process determines if the player's bankroll level has changed (for example, changed levels from a set of defined levels such as high, medium, and low).

If the player's bankroll level has changed at block 614, the depicted alternative process will consider one or more additional factors to determine a new desired volatility level based on the new bankroll level (block 616). The additional factors may be considered directly (that is, employed directly in the decision logic), or combined in some metric such as a metric to indicate how risk averse a player may be. These factors or metric are used, in this embodiment, together with the bankroll size to determine a desired volatility or choose a paytable. Some additional factors are shown in FIG. 6, items 617-622, although this is not limiting and a variety of other factors may be used. Each one of the depicted factors is considered in the system herein by using one or more variables having a value indicating the factor as it is calculated or measured. A change in bet level (item 617) is one of the possible factors that may be employed along with a bankroll change to adjust the desired volatility. Another factor that may be employed is an indicator of player risk aversion (item 618). This may be calculated from one or more of a variety of factors such as bankroll size, wager size, and time between wagers. Item 619 provides another factor which may be considered to determine any volatility adjustment, which is the length of the player's gaming session. The time of day may also be used (item 620), with different volatilities given at closing times or near meals. Item 621 takes into consideration the direction of changes in player's bankroll, and item 622 considers the rate of change in a player's bankroll, which may be calculated over a specified time period or over a specified number of wagers. Other aspects of the player's history may also be taken into account, such as their typical betting amount or the type of gaming machines at which they typically play (especially whether they prefer high or low volatility machines). The decision may also take into account the number of possible wagers remaining in a player's bankroll. Yet another factor that may be added into the determination of what desired volatility to use is the player's movement between gaming machines. That is, moving to a different gaming machine may sometimes be interpreted as the player's desire to play a different game with a different volatility. Any of the above-listed factors may be used separately or together in any subcombination with the player's bankroll in the process of determining the desired volatility.

After determining the additional factors to be used at block 616, the new desired volatility level is determined at block 624. This desired volatility is used to choose a new paytable to activate in the game at block 626. At this point, the game is ready to receive the next wager from the player and returns to step 608. In such a manner, the wagering or payout volatility of the gaming machine is adjusted based on the bankroll deposited by the player. It should be noted that the process at block 626, and the similar function described with regard to FIG. 4, block 418, may include displaying a visual indication to the player that the paytable has changed to a different volatility. This may take the form of changing the symbols used to convey the game, for example in preferred 5-reel slot machine game embodiments, the symbols on the reels may change. The volatility change may also be indicated by changing the background graphics or colors, or changing a visible indication of the paytable or partial paytable displaying, for example, the bonus prizes or maximum prizes available. Other embodiments may not include a visual indication of the volatility change when it happens, but instead may list the various possible volatilities in the gaming machines “payout” screen or similar screen, accessible to the player through the gaming machine controls.

The above described preferred embodiments are intended to illustrate the principles of the invention, but not to limit the scope of the invention. Various other embodiments and modifications to these prefelTed embodiments may be made by those skilled in the art without departing from the scope of the present invention.

As used herein, the terms “comprising,” “including,” “carrying,” “having,” “containing,” “involving,” and the like are to be understood to be open-ended, that is, to mean including but not limited to.

Any use of ordinal terms such as “first,” “second,” “third,” etc., to refer to an element does not by itself connote any priority, precedence, or order of one element over another, or the temporal order in which acts of a method are performed. Rather, unless specifically stated otherwise, such ordinal terms are used merely as labels to distinguish one element having a certain name from another element having a same name. 

1. A method for adjusting the volatility of payouts in a wagering game, the method comprising: (a) determining a game player's bankroll amount comprising cash or credits available for wagering; (b) determining a desired volatility based on the game player's bankroll amount; (c) selecting a payout table based on the desired volatility; (d) receiving a wager input from the game player effective to place a wager from a gaming machine; (e) conducting a game with the selected payout table; and (f) displaying results of the conducted game at the gaming machine.
 2. The method of claim 1 further comprising determining the desired volatility after detecting a change in the game player's bankroll level.
 3. The method of claim 1 further comprising determining the desired volatility after the wager input is received.
 4. The method of claim 1 further comprising determining the desired volatility based on the game player's wager level as well as the game player's bankroll amount.
 5. The method of claim 1 further comprising determining the desired volatility based on a time of play by the game player as well as the game player's bankroll amount.
 6. The method of claim 1 further comprising determining the desired volatility based on a change in player stations as well as the game player's bankroll amount.
 7. The method of claim 1 further comprising determining the desired volatility based on a history of the game player as well as the game player's bankroll amount.
 8. The method of claim 1 further comprising determining the desired volatility based on a number of possible bets remaining in the game player's bankroll as well as the game player's bankroll amount.
 9. The method of claim 1 further comprising determining the desired volatility based on a time before closing of a gaming establishment, as well as the game players bankroll amount.
 10. A gaming system comprising: (a) a number of gaming machines, each gaming machine including (i) a display arrangement having one or more display devices, and including (ii) a player input device arrangement having one or more player input devices; (b) an award controller adapted for (i) determining a desired volatility based on a game player's bankroll amount, for (ii) selecting a payout table based on the desired volatility, for (iii) receiving a wager input from the player effective to place a wager from a gaming machine, for (iv) conducting a game with the selected payout table; and (c) a game controller arrangement adapted for causing the display arrangement for one or more of the number of gaming machines to display gaming results for the conducted game.
 11. The gaming system of claim 10 in which the award controller further comprises a tangible computer readable medium storing a bankroll data structure including multiple bankroll levels each associated by the bankroll data structure to a respective desired payout table.
 12. The gaming system of claim 11 in which the bankroll data structure further includes a desired volatility level for each of the multiple bankroll levels.
 13. The gaming system of claim 10 in which the award controller is adapted for determining the desired volatility after detecting a change in the game player's bankroll level.
 14. The gaming system of claim 10 in which the award controller is adapted for determining the desired volatility based on a change in player stations in addition to the game player's bankroll.
 15. The gaming system of claim 10 in which the award controller is adapted for determining the desired volatility based on a metric indicator of the game player's risk aversion.
 16. A program product embodied in one or more tangible computer readable media, the program product comprising program code executable for: (a) determining a game player's bankroll amount comprising cash or credits available for wagering; (b) determining a desired volatility based on the game player's bankroll amount; (c) selecting a payout table based on the desired volatility; (d) receiving a wager input from the game player effective to place a wager from a gaming machine; (e) conducting a game with the selected payout table; and (f) displaying results of the conducted game at the gaming machine.
 17. The program product of claim 16 further comprising program code executable for reading a first tangible computer readable medium storing a bankroll data structure including multiple bankroll levels each associated by the data structure to a respective desired payout table.
 18. The program product of claim 17 in which the bankroll data structure further includes a desired volatility level for each of the multiple bankroll levels.
 19. The program product of claim 16 in which the program code is executable for determining the desired volatility after detecting a change in the game player's bankroll level.
 20. The program product of claim 16 in which the program code is executable for determining the desired volatility based on a metric indicator of the game player's risk aversion. 